1. Field of the Invention
The present invention relates to a multi-channel acoustic apparatus with a DVD reproduction function. “Dolby” and “Pro Logic” used in the specification are trademarks of Dolby Laboratories.
2. Description of the Prior Art
[1] In a multi-channel audio system, a surround delay adjustment and a level adjustment between speakers are performed in order to suitably reproduce a sound source. In the case of Dolby digital, a surround delay time period is adjusted such that a sound from a surround speaker and a sound from a front speaker simultaneously reach a listener. In Dolby Pro Logic in which separation between channels is not superior to that in the Dolby digital, a surround delay time period is adjusted such that a sound from a surround speaker reaches a listener immediately after a sound from a front speaker by a little longer (approximately 15 ms) delay.
In the same environment, there is thus a predetermined relationship in surround delay time period between the Dolby digital and the Dolby Pro Logic. If the surround delay time period is adjusted in one decode mode, therefore, the most suitable surround delay time period can be also set with respect to the other decode mode.
Developed as the multi-channel acoustic apparatus is one comprising a DVD reproduction control unit for controlling the reproduction of a DVD and a system control unit for controlling the overall apparatus and controlling the reproduction of another input source other than the DVD, and capable of changing the setting of a surround delay time period in each of both the control units.
In this type of multi-channel acoustic apparatus, when the surround delay time period in the Dolby digital or the Dolby Pro Logic is adjusted by the DVD reproduction control unit, the surround delay time period is controlled by the DVD reproduction control unit at the time of reproducing the DVD. Accordingly, the surround delay time period adjusted by the DVD reproduction control unit is reflected. In a case where the input source other than the DVD is reproduced and a case where the Dolby Pro Logic is decoded by the system control unit during the reproduction of the DVD, however, the surround delay time period adjusted by the DVD reproduction control unit is not reflected.
An object of the present invention is to provide a multi-channel acoustic apparatus with a DVD reproduction function, in which in a case where a surround delay time period is adjusted by a DVD reproduction control unit, the adjusted surround delay time period is automatically reflected in a Dolby Pro Logic decoder controlled by a system control unit.
[2] A multi-channel acoustic apparatus with a DVD reproduction function comprising a DVD reproduction unit and a built-in amplifier comprises the function of outputting a test tone (a noise) to each of channels and adjusting for each of the channels the output level of the channel such that a user can adjust an output level between speakers (channel balance adjustment). In a system capable of decoding a Dolby digital program source, a test tone is outputted to five channels, i.e., a left front channel, a center channel, a right front channel, a right surround channel, and a left surround channel at the time of adjusting an output level between the speakers, and the test tone is outputted from the corresponding speaker after being circulated for each of the channels.
Developed as the multi-channel acoustic apparatus with the DVD reproduction function is one comprising a DVD reproduction unit comprising a DVD reproduction control unit, and a system control unit for controlling the overall acoustic apparatus and controlling the reproduction of another input source other than a DVD.
In this type of multi-channel acoustic apparatus, when an attempt to perform channel balance adjustment processing only by the system control unit is made, a method of displaying a channel, whose output level is being adjusted, to which a test tone is outputted from a speaker and the output level of the channel is restricted on a display unit such as an FL (Fluorescent) or an LED (Light Emitting Diode) controlled by the system control unit, and a device capable of outputting a noise to each of channels, for example, a Dolby Pro Logic decode IC controlled by the system control unit is required in addition to a device for reproducing a DVD.
An object of the present invention is to provide a multi-channel acoustic apparatus with a DVD reproduction function capable of on-screen displaying a channel whose output level is being adjusted, information representing the channel, and the output level of the channel at the time of adjusting channel balance and making it easy to adjust the channel balance.